Kalshi, Polymarket July Volume Hits Record $50.59 Billion on World Cup Boost

Monthly trading volume on prediction-market platforms Kalshi and Polymarket reached a record in July, lifted by strong interest during the FIFA World Cup.

The Block reported on August 3 that combined July trading volume for Kalshi, Polymarket and Polymarket US totaled $50.59 billion. That was up 7.8% from $46.95 billion in June.

Kalshi accounted for the biggest share, with $37.7 billion in trading volume, up 14% from a month earlier.

Polymarket's volume fell 26% from June to $7.9 billion. Polymarket US, which serves American users, posted a 54% increase to $5 billion. Even so, combined volume for Polymarket and Polymarket US edged down to $12.9 billion from $14 billion.

Polymarket US is regulated by the US Commodity Futures Trading Commission. The platform opened its service to users across the US after scrapping its waitlist system in May.

The jump in July volume was driven mainly by the World Cup. During the tournament, which ran from June 11 to July 19, about $1.9 billion was traded on Kalshi's market for the Spain-Argentina final, while roughly $4 billion flowed into Polymarket's market on the World Cup winner.

Trading momentum cooled after the tournament ended. Open interest across the three platforms fell to about $1.2 billion at the end of July from roughly $2 billion at the start of the month.

The prediction-market industry continues to face regulatory disputes in the US despite its growth. More than 10 state governments have moved against Kalshi and Polymarket, arguing that their sports-event contracts amount to unlicensed gambling. Both companies are continuing their legal fight alongside the CFTC, arguing that federal regulation takes precedence over state law.